The proposed mentored research project (F31) is a two-year plan to develop the candidate into an independent developmental psychopathologist. The candidate outlines a proposal integrating coursework, consultation with established researchers, and an independent research program that will enable the candidate to: (1) gain specialized knowledge of issues related to developmental psychopathology in youth, (2) acquire training in designing, conducting, and disseminating findings from longitudinal studies, and (3) enhance skills related to statistically modeling multi-wave longitudinal data. Extensive research demonstrates that rates of depression are rising in adolescents and that the age of onset for depression is becoming younger.1,2,3 In response to these alarming statistics, a greater emphasis has been placed on identifying vulnerabilities to depression at a young age in the hope of preventing the onset of the disorder. An emerging area of research on this topic identifies anxiety as an important risk factor for depression.4 The present research seeks to build upon these initial findings by further investigating the role anxiety may play in the onset and maintenance of depressive symptoms and episodes during adolescence. Moreover, the present study tests whether anxiety interacts with specific cognitive (rumination, interpretation biases, and self-criticism) or interpersonal (insecure attachment, maladaptive parenting styles, low child-parent affect, and low social support) vulnerabilities to better understand which anxious youth are most at-risk for developing depression, and the role anxiety may play in explaining elevated levels of depression found in adolescent girls compared to boys. Data will be collected from an ongoing multi-wave longitudinal study which follows 682 youth ranging in age from 8 to 17. An emphasis of this research project is the use of a multi-method approach in measuring vulnerabilities and internalizing disorders, including self-report, parent-report, clinicl interviews, a computer task, and a parent- child interaction task. It is believed the study's design, coupled with this training, provides the best opportunity to fulfill the project's primary objectives, and supply the field with new findings concerning the relation between anxiety and depression. Through this research a more comprehensive model for the development of depression can be gained and a better understanding of how to prevent the disorder during adolescence can be obtained. PUBLIC HEALTH RELEVANCE: The present study will examine the role anxiety plays in the development of anxiety during adolescence. The goal of this research is to discover new developmental pathways to depression, which will allow prevention programs to better target which individuals are most at-risk for developing the disorder at an early age.